With the previous covid detection apps (the covid API from Apple/Google) privacy was really a key design goal and I had no issues using that.

With these new QR apps (the EU CoronaCheck program) there was less of a focus on this. Part of that makes sense, as it's meant to identify the user's status it's not possible to be completely anonymous. But there has hardly been any info on whether the apps phone home. Also, the Apple/Google API apps from each country were almost all open source. None of that now. It's taken for granted that privacy is not a concern anymore, for some reason.